Propecia is a prescription medication used to treat male pattern hair loss. Its active ingredient finasteride is a synthetic inhibitor of the enzyme 5-alpha-reductase. By blocking the conversion of testosterone into dihydrotestosterone the drug reduces the levels of this potent androgen in scalp tissue. Dihydrotestosterone is the hormone that promotes the miniaturization of hair follicles over time. The decrease in dihydrotestosterone slows the progression of follicle shrinkage and can stimulate partial regrowth in some men. The pharmacological effect is achieved through competitive inhibition of the type ii isoform of 5-alpha-reductase, leading to systemic reduction of dihydrotestosterone concentrations. This mechanism provides a targeted approach to modulating hormonal pathways associated with androgenetic alopecia.

Propecia is a brand name for the drug finasteride a synthetic 5-alpha reductase inhibitor. It is used therapeutically to treat male pattern hair loss. The medication works by reducing the conversion of testosterone into dihydrotestosterone. This action helps to decrease size of enlarged prostate cells and slows hair follicle miniaturization. Pharmacologically it binds to the type ii 5-alpha reductase enzyme in scalp and prostate tissue. The reduction of dihydrotestosterone levels interrupts androgen driven pathways that drive hair loss.

Propecia may cause sexual dysfunction including decreased libido and erectile difficulty. Some users report breast tenderness or enlargement. Mood changes such as depression or anxiety have been documented in rare cases. Rare allergic reactions can lead to rash or swelling of the face and tongue. Long term use may result in persistent sexual side effects even after discontinuation. The likelihood of these effects varies among individuals and is not guaranteed to occur.

Propecia may cause changes in sexual function including decreased libido and erectile dysfunction. Some users experience breast tenderness or enlargement. Occasional mood changes such as depression or anxiety have been reported. Rarely, skin reactions like rash or itching can occur. In a small number of cases, testicular pain or swelling has been documented. Hormonal fluctuations may lead to occasional dizziness or light-headedness. These effects vary among individuals and often diminish over time.